library ieee;use ieee.std_logic_1164.all;use ieee.numeric_std.all;use work.Constants.all; entity Strober is    port (reset, clk : in  std_logic;       strobe : in std_logic;       sample : in std_logic;       env_col : in col;       env_row : out row;       sample_col : out col; --rows and cols to be analysed       sample_row_number : out row_number       );    end Strober;architecture Strober_arc of Strober isfunction decode_row(inp: row_number) return row isvariable rowstrobe : row;begin	case inp is	when 11 => rowstrobe := "011111111111";	when 10 => rowstrobe := "101111111111";	when 9 => rowstrobe :=  "110111111111";	when 8 => rowstrobe :=  "111011111111";	when 7 => rowstrobe :=  "111101111111";	when 6 => rowstrobe :=  "111110111111";	when 5 => rowstrobe :=  "111111011111";	when 4 => rowstrobe :=  "111111101111";	when 3 => rowstrobe :=  "111111110111";	when 2 => rowstrobe :=  "111111111011";	when 1 => rowstrobe :=  "111111111101";	when 0 => rowstrobe :=  "111111111110";	when others => rowstrobe := "111111111111";	end case;	return rowstrobe;end decode_row;    begin      strober: process   variable row_counter : integer;      begin       wait until rising_edge(clk);       if (reset = '1') then           env_row <= "111111111111";           row_counter := 0;              elsif (strobe = '1') then           if (row_counter < number_of_cols-1) then           	row_counter := row_counter + 1;           elsif(row_counter = number_of_cols-1)then           	row_counter := 0;           end if;           env_row <= decode_row(row_counter);                  elsif (sample ='1') then --first sample           sample_row_number <= row_counter;           sample_col <= not env_col;       end if;   end process;      end strober_arc;